I've been on an extended hiatus so I'm out of the loop when it comes to value, I've also improved quite a bit since I last sold my art here! I don't want to under or over value my work so any help would be appreciated, here's some things I've done recently:

As a side note all of my work is done on 1000 x 1000 canvases, I just resized everything here so it fit on the forum I hate posting tons of links XP

Do you mean in SP or actual money? When I sell my art I go by how long it takes and how expensive the materials I use are, and how much of the materials I use. I drew a single pokemon recently and sold it for $50. it was over 10 hours work, used up a lot of my purple pencil crayons, and they are prismas so quite expensive. if that helps give you an idea. Since yours is digital obviously cancel out the materials part, but if you're putting a lot of work into it i wouldn't be shy to charge more. these are lovely by the way!

Taking your skill level into consideration (which is pretty good right now), I would ask about 30mil sP or 1300 CSC for the detailed coloured ones, and less for the flat colours :)